var map = new maptalks.Map('map', {
  center: [-0.113049, 51.498568],
  zoom: 6,
  pitch: 40,
  attribution: {
      content: ' &copy; carto'
  },
  // add 2 TileLayers with a GroupTileLayer
  baseLayer: new maptalks.GroupTileLayer('base', [
      new maptalks.TileLayer('tile2', {
          urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_nolabels/{z}/{x}/{y}.png',
          subdomains: ['a', 'b', 'c', 'd']
      }),

      new maptalks.TileLayer('boudaries', {
          'urlTemplate': 'https://{s}.basemaps.cartocdn.com/dark_only_labels/{z}/{x}/{y}.png',
          'subdomains': ['a', 'b', 'c', 'd']
      })
  ])
});

